Automatic dishwashing detergents are well-known in the art. Most of the automatic dishwashing detergents currently available are suitable for their intended purposes, i.e., effectively cleaning, and leaving previously soiled eating and cooking utensils in a generally spot-free, clean condition.
Known automatic dishwashing detergents contain some combination of one or more of three ingredients, including bleach, caustic soda, and phosphates. These substances can be deleterious, for various reasons.
For example, phosphates are minerals that act as water softeners and are considered by some to be among the worst pollutants found in detergents. Phosphates are a nutrient, and act as a fertilizer for algae. Thus, when phosphates enter waterways, they promote the growth of algae and other plants. In the presence of large amounts of phosphates and other similar nutrients, excessive algae growth occurs. This causes odors and creates hypoxic conditions.
Some states have banned the use of phosphates in all detergents, other than automatic dishwasher detergents. Thus, phosphate-free general purpose detergents and clothing detergents are readily available.
Caustic soda is also considered to be a contaminant of groundwater. For example, alumina plants use and discharge caustic soda into the groundwater adjacent their plants, and such groundwater contamination is considered to be a significant environmental problem. Moreover, the caustic soda can impart to the automatic dishwashing detergent a noticeable odor, which can be described as a “choking-type” odor. Moreover, an etched film can be irreversibly formed on the surface of glassware that has been repeatedly washed with caustic soda-containing automatic dishwashing detergents.
Bleach provides automatic dishwashing detergents with some disinfecting capabilities. While bleach in groundwater is not generally deemed to be deleterious, the removal of bleach from an automatic dishwashing detergent would lower the cost of that dishwashing detergent. Bleach, especially when combined with caustic soda, can contribute to the choking-type odor that may be perceived in some other automatic dishwashing detergent products.
It would be desirable to provide an automatic dishwashing detergent which is free of phosphates. It would further be desirable to provide an automatic dishwashing detergent which is free of caustic soda. Finally, it would be desirable to provide an automatic dishwashing detergent which is free of bleach.